DESCRIPTION: The goal of this project is to find a combination of chemoprevention treatments that has substantial efficacy against prostate cancer in relevant prostate cancer model systems and that can rapidly be moved to human clinical trials. Candidate treatments must not only have the desired efficacy and be amenable to combination with other agents, but must also be inexpensive, easy to administer and non-toxic. The chemopreventive activity of the treatments must be directed against prostate cancer growth, progression an metastasis because these are the most relevant targets for prostate cancer chemoprevention. An implication is that no single chemoprevention treatment is likely to result in substantial inhibition of all these stages in prostate cancer development. The PI proposes to determine whether soy protein isolate, green tea, and selenium-containing brewer's yeast inhibit prostate carcinogenesis and prostate cancer metastases in rat models, whether green tea and selenium compounds inhibit the growth of human prostate cancer cells in vitro, and whether any of the three agents inhibit the growth of human prostate cancer xenografts in nude mice and affect the production of PAA by these human cells and xenografts. In future studies, the PI will determine which combination of substances (not limited to the agents mentioned) which have individual efficacy against prostate cancer results in the most pronounce inhibitory effect on prostate carcinogenesis and metastasis in rat models and on the growth of human prostate cancer cells in vitro and of human prostate cancer xenografts in nude mice.